Congratulations!
I wouldn't be without my two kids (24 & 20) as I'm hoping they will start taking care of me soon!
If you are going to carry your baby before it sits up, you can get carrycots that can be secured by the cental rear seat belt.
My handbook indicates that SAAB did sell seats (in '96) in three different sizes but, unless they do a part exchange, you could find yourself needing a replacement at at 6 monthly intervals!
Apparently, there are mounting points under the front seats that can be used to secure front and rear types but, since kids can't legally be carried in the front in an adult belt until they're 10 or 12, you might as well start him/her off in the back.
Anyway, the handbook reference to airbags clearly states that baby seats must be placed in the back, which suggests that it may not be possible to disable just the front one.
Something to consult a SAAB dealer about perhaps?